Yarn trapping and severing means for circular knitting machines



Jan. 1, 1952 A. M. BROWN 2,580,513

YARN TRAPPING AND SEVERING MEANS FOR CIRCULAR KNITTING MACHINES Filed Sept. 2, 1950 4 Sheets-Sheet 11 Inventor Jan. 1, 1952 Y BROWN 2,580,513

YARN TRAPPING AND SEVERING MEANS FOR CIRCULAR KNITTING MACHINES Filed Sept. 2, 1950 4 Sheets-Sheet 2 I nvenlor HUI/TM Bram By M? 1952 A. M. BROWN 2,530,513

YARN TRAPPING AND SEVERING MEANS FOR CIRCULAR KNITTING MACHINES Filed Sept. 2, 1950 4 Sheets-Sheet 5 Jan. 1, 1952 A M BROWN 2,580,513

YARN TRAPPINC' AN'D SEVERING MEANS FOR CIRCULAR KNITTING MACHINES Filed Sept. 2, 1950 4 Sheets-Sheet 4 Inventor Patented Jan. 1, 1952 YARN TRAPPING AND SEVERING MEANS FOR CIRCULAR KNITTING MACHINES Albert Matthews Brown, Leicester, England, as-

signor to G. Stibbe & Co. Limited, Leicester, England, a British company Application September 2, 1950, Serial No. 183,037 In Great Britain September 27, 1949 7 Claims.

This invention relates to circular knitting machines, and has reference particularly to means employed in such machines for trapping and also severing yarns uponwithdrawal from knitting.

Yarn trapping and severing means of the kind with which the invention is concerned comprise a fixed member and a relatively movable trapper jaw which co-operate to form a trapper, and, combined with the said trapper, a cutting device consisting of relatively movable cutter blades. Thus, a yarn withdrawn from knitting is severed, by the cutting device, from the fabric or article being knitted, and the loose end of the cut yarn extending from the yarn guide is disposed between the operative edge of the movable trapper jaw and the opposed surface of the aforesaid fixed member where it is trapped until again required for re-introduction to the needles of the machine for knitting.

Yarn trapping and severing means of this kind are designed for use in conjunction with yarn supplying mechanism including a plurality of yarn guides adapted to deal with respectively diiferent yarns and to be operated selectively for the purpose of introducing desired yarns to, and withdrawing same from, the needles at predetermined times, according to requirements.

Moreover, the invention is applicable exclusively to circular knitting machines (more especially for the production of seamless hosiery) equipped with a welt mechanism comprising a dial with welt instruments or transfer bits in association with a dial cam-system for co-operation with the needles in the production, automatically, of inturned welts.

The object of the present invention is to provide, in a circular knitting machine furnished with yarn trapping and severing means of the kind concerned and welt mechanism as aforesaid, particularly :simpleand efficient means for actuating the cutting device.

Another object is to provide improved interconnected means for effecting conjoint operation of the trapper and the cutting device, as will be hereinafter described.

According to this invention oneoi? the cams incorporated in the welt cam system or a part movable therewith is operatively connected with the cutting device'and adapted normally to maintain the said device closed, and the means emplayed for rendering the'said cam operative in the making of a welt are additionally operable at required times to move the cam or the associated part in such a, way as to actuate the cutting device. This .is made possible by reason of 2 the fact that the said welt cam and its actuating means (usually a lever operable from a control unit) have a certain amount of lost motion.

The particular cam used for rendering the welt instruments or transfer bits active at the commencement of knitting a welt may advantageously be operatively connected with the cutting device for the intended purpose.

In a convenient embodiment of the invention,

the cutting device comprises fixed and relatively movable blades. arranged scissor fashion, the movable blade being secured to a spindle provided with a crank or an eccentric arranged to work in a slot or between guides inor on the welt cam concernedor the aforementioned. part movable therewith.

The relatively movable trapper jaw may be controlled in any conventional or other suitable manner independently of the cutting device. Preferably, however, the said jaw is controlled in the manner described in my co-pending application No. 154,495, now abandoned, filed April '7, 1950. That is to say, the movable trapper jaw maybe adapted to be normally pressed upon, and thereby locked in co-operative relationship with the fixed trapper member, by the same welt cam, or part movable therewith, from which the cuting device is actuated, this pressure upon the trapper jaw being relieved whenever the welt cam or associated part is moved to open the cutting device. In this combined arrangement, therefore, the movable trapper jaw and the movable scissor blade are .conjointly controlled from the same welt cam (or part combined therewith) in such a manner that the cutting device is opened to receive a yarn Withdrawn from knitting simultaneously with relief of the pressure upon the movable trapper jaw and, conversely, the cutting device is closed to sever the withdrawn yarn consequent upon movement of the Welt cam or associated part to lock the movable trapper jaw firmly in co-operative relationship with the opposed surface of the fixed trapper member.

In order that theinvention may be more clearly understood and readily carried into practical effect, particular illustrative embodiments thereof applied to a circular seamless hose or like machine having a welt mechanismand equipped with a plurality of interchangeable yarn guides at a common feeding location will now be described with reference to the accompanying drawings, wherein,

Figure 1 is a general perspective view depicting the yarn trapping and severing means and so much of the ,welt mechanism as is necessary trapper jaw 2.

steam to illustrate the principle of the invention as embodied in one example thereof,

Figure 2 is a further general perspective view illustrating the preferred embodiment of the invention wherein the cutting device (shown closed) and the trapper are both controlled from a single Welt cam,

Figure 3 is a similar perspective view to Figure 2 but with the cutting device shown open, and the levers for controlling the welt cams removed for the sake of clarity.

Figure 4 is a plan view of the said yarn trapping and severing means shown in relation to the latch ring and the interchangeable yarn guides of the machine,

Figure 5 is a part-sectional elevation as seen in the direction of the arrow A in Figure 4, that is to say from the front of the machine,

Figure 6 is a further part-sectional elevation as seen in the direction of the arrow B in Figure 4,

Figure '7 is a detail sectional view illustrating ;the cutting device, shown open, and the interthe machine are operated and controlled.

Like parts are designated by similar reference characters throughout the drawings.

Referring to Figure 1, wherein the general principle of the invention is illustrated, it will be seen that the yarn trapping and severing means comprise a fixed member I and a pivoted trapper jaw 2 which co-operate to form a trapper T, and an associated cutting device C consisting of a fixed scissor blade 3 and a relatively movable scissor blade 4. In this particular example, the

trapper T is controlled quite independently of the cutting device C, from a fulcrumed lever 5 one end of which is connected, through the medium of a link 6, with a tail portion 2a of the pivoted The lever 5 is connectable with connections controlled from controlling or timing means such as a control drum (not shown) fitted with cams. Normally, the trapper jaw 2 is held in co-operative relationship with the fixed member I, but whenever a yarn is withdrawn from knitting, the jaw 2 is first raised to open the trapper and so enable it to receive the said yarn and then lowered to trap and hold the latter. In accordance with the characteristic feature of the present invention, a welt cam I, known as the "setting-up cam, for rendering welt instruments or transfer bits active for the purpose of receiving loops from between alternateneedles at commencement of knitting a welt, is employed for normally maintaining the cutting device C closed, and the conventional controlled lever 8 for operating the welt cam I is used for actuating the latter in such a manner as to raise the movable scissor blade 4 and so open the cutting device C at required times and conjointly with operation of the trapper T.

The cam I, which is movable within a dial cam cap ring 9 and normally held up in an inoperative position clear of a dial carrying the welt instruments or transfer bits,- is attached to a small carrier block H! which is in turn secured to a tubular member ll arranged for sliding movement up and down on a vertical hollow post [2 containing a compression spring 13. At its upper end this spring bears upon the upper closed end of the tubular member II. A lug M on the tubular member I! is drilled through vertically for engagement with the shank of a fixed screw or pin i5 whereby the welt cam i is guided. The aforementioned lever B is for action upon the top of the upper closed end of the tubular member I i.

Now the cam 1 has lost motion in that it can be depressed a certain distance without aifecting the welt instruments or transfer bits, and this fact is relied on for the purpose of the invention. As will be seen the welt cam l is extended upwardly at 1a and has formed therein a horizontal slot I5. Into this projects the cranked end Ila of a horizontally disposed spindle I! mounted to turn in a bearing formed in a bracket l8 servin also to carry the fulcrumed trapper-controlling lever 5. The scissor blade 3 is fixed to the side of the bracket 18 remote from the trapper T.

The spindle Il' projects through the fixed scissor blade 3 and has connected thereto the movable scissor blade 4. A compression spring l9 interposed between a collar 20 or flange on the spindle l1 and the opposing surface of the bracket 13 serves to hold the scissor blades together yieldingly.

Thus, whenever the spring-controlled tubular member I l is depressed, as a consequence of suitable actuation of the lever B, the cranked spindle will be turned to open the cutting device. Conversely, whenever the welt cam I is released and moves upwards under the sprin action to its permitted extent, the cranked spindle ll will be turned in the reverse direction to close the cutting device C. A few yarns which have been withdrawn from knitting and severed by the device C are indicated at Y.

The preferred embodiment of the invention, in which both the cutting device C and the trapper T are controlled from the same welt cam I will now be described with reference to Figures 210. This preferred embodiment is applied to a machine furnished with a plurality of interchangeable and selectively operable yarn guides such as 2| for supplying respectively different yarns Y to the needles (not shown). These guides, or feeders as they are often called, extend through a gap 22a formed in the conventional latch ring 22 (see Figure 4). In conjunction with the yarn guides 2l' there is provided a common trapper comprising a fixed horizontal plate 23 carried by a central hub or boss 24, and a pivoted trapper jaw 25 which is disposed above the said plate and fulcrumed on a screw 26 in the hub or boss, the Whole being located above a dial 2! (Figure 5) containing a circular series of welt instruments or transfer bits 28.

The welt instruments or transfer bits 28 are formed with upstanding actuating butts 28a and are thereby adapted to be operated and controlled by a cam system associated with a dial cam cap ring 29. As shown more clearly in Fi ure 10, the inner peripheral edge of 'the ring 29 is conventionally contoured for the purpose in view and, within the said ring, there are propush all of the welt instruments or transfer bits 28 radially outwards, as permitted by the concave recess 29a formed in the dial cam cap ring 29, and so render the instruments or bits active at .theilocation .D .ior the purpose of receiving -loops .iromlbetween alternate needles at the commencement of knittinga welt. The two cams 30 and 31,, on the other hand, are movable together and adapted, when both depressed into the path of the butts 28a, to actuate the welt instruments or bits .28 suchwise as to effect transference of the retained loops back tothe needles at the termination of the knitting .of the welt.

The cam 1, which is normally held up in an inoperative position clear of the dial (21., is attachedto a small carrier block 32 which is in turn :secured to a tubular member 33 arranged, like the corresponding member in Figure 1, for slid- .ingrmovement up and down on .a vertical hollow post:34 containing a compression :spring 35. At its upper end'this spring, as .shown .in Figure rbears upon the upper :closed end .of the tubular :member 33. The Icam carrier block 32 is drilled through vertically .for engagement with the shank136a of a fixed screw 'or pin .36 whereby it is guided. For depressing the .member 33 and rendering .the cam I operative at appropriate times, against the action of the compression spring 35, there is provided a centrally pivoted .slever *3! (Figure 2). the operative end 31a of whichfbears upon the top of the upper closed end of the tubular member 33. The lever 3'! is "actuated from the control drum of the machine (not shown) through the medium of a cam lever and an intermediate link.

The cams 30 and 31 are attached to a common carrier block 38 which is mounted and adapted to be operated and controlled in a similar manner to the carrier block 32. That is to sav, the :block 38 is secured to a tubular member 39 arranged 'for sliding movement up and down a spring-controlled "hollow post (not shown). The cam carrier block-38 is drilled for engagement with the shank of a fixed screw or pin such as M! (Figure 4) whereby it is guided; A centrally pivoted lever 4|, actuated from the control drum, through the medium of a further cam lever and an intermediate link, is'provlded for action upon the tubular member 39.

The cam carrier block32 has lost motion in that it can be depressed a certain distance without affecting the welt instruments or transfer bits 28. The tail end of the pivoted trapper jaw 25-that is to say the end at the side of the fulcrum 2!; remote from the trapping edge 25a of the jaw-is provided with an extension or an equivalent formation such as 42 which is bent out of the plane of the jaw and into the path of the cam carrier block 32. Accordingly. whenever the cam carrier block 32 is permitted to move upwards under the action of the compression spring 35, the said block comes into contact with and presses upwardsupon the underside of the tail extension or formation 42 as depicted in Figure 2, thereby forcing the operative edge 25:: of the trapper ,jaw 25 downwards and securely looking it in cooperative relationship with the fixed trapper plate 23. To relieve the pressure, the conventional pivoted'lever 31 is turnedwithout rendering the cam l operative, to anlextent just sufilcient to move the cam carrier or block 52 away from the tail extension or formation 42 on the jaw 25, so releasing the latter. Special cams (i. e. cams not shown, additional to those necessary for operating the welt mechanism), are provided on the control drum for suitably actuating the pivoted lever 31 for relief of the pressure on the trapper jaw 25 at predetermined times. It is to be clearly understood, however, that when the pressure upon the movable trapsecured by a screw 5|.

per jaw 25 is relieved, the-said jaw. is not operated and separated from the fixed horizontal plate 23; it merely remains where it is and acts under gravity to maintain at least some measure of control over the idle yarns already in the trapper. .In short, the relief of pressure permits separation of the jaw 25 from the .fixed plate 23 merely to the small extent necessary to permit of introduction into the trapper of a yarn withdrawn from knitting.

The welt cam l is extended upwardly at 1a (as in the first described example) and has formed therein a short horizontal slot [6. Into this slot projects the cranked end 43a of a horizontally disposed spindle 43, which is mounted to turn in a tubular bearing (see Figure 9) fixed in a bracket 45 secured to the central hub or boss 24. Secured by a screw 46 to the side of the bracket 45 remote from the movable trapper jaw 25 is one scissor blade 41 of a cutting device. The operative portion 47a of the fixed blade 41 extends outwardly from the bracket 45-immediately above the fixed horizontal plate 23. As shown in Figure 9, the fixed scissor blade 41 is also provided with an integral upstanding portion "41b in which is formed a hole 48 adapted to receive the appropriate end of the tubular bearing '44 projecting slightly from the bracket 45. In this way the projecting end of the said bearing serves to locate the fixed scissor blade in position.

Thespindle 43 projects right through the tubular bearing-24 and has clamped upon its end a member 49 to which a movable scissor blade 50 is To prevent it turning on the member 49, the scissor blade 53 has formed therein a hole 52 (Figure 9) through which the spindle '43 extends. Accordingly, whenever the :spindle is turned, the movable scissor blade 50 will turn with it. Adiacent to its cranked portion 430. the spindle 43 has fitted thereon. a collar 53, or is flanged, and there is interposed between the collar or flange and the bracket 45 a compression spring 54 which surrounds the tubular bearing 44 and serves 'to hold together the scissor blades 41 and 50 yieldingly. The construction and arrangement are therefore such that whenever the welt cam l is depressed, not only will the pressure on the pivoted trapper jaw 25 be relieved, but the cranked spindle 43 will be turned to raise the scissor blade'5il and so open the cutting device. Conversely, whenever the Welt earn 1 is released and permitted to move upwardly, the operative edge 25a of the trapper jaw 25 will be forced downwardsand locked in co-operative relationshipwith the fixed trapper plate 2 3, and

the spindle 43 will be simultaneously turned in the reverse direction to close the cutting device.

"In a multiple trapper unit, that is to say a unit comprising a main trapper and cutter and auxiliary trappers and cutters, the construction herein described may apply to either or all of such trappers and cutters.

What I claim then is: 1. In a circular knitting machine, in combination, yarn trapping means consisting of a fixed normally to maintain the said device closed, and means adapted not only to render the said welt cam operative in the making of a Welt but also to move the said cam at required times suchwise as to actuate the cutting device.

7 2. In a circular knitting machine, in combination, yarn trapping means consisting of a fixed member and a relatively movable trapper jaw adapted to trap and hold between them a yarn withdrawn from knitting, an associated cutting device comprising relatively movable scissor blades for severing a withdrawn yarn, a welt mechanism comprising a dial equipped with welt instruments and cams for actuating the said instruments in the production of welts, including a bination, yarn trapping means consisting of a' fixed member and a relatively movable trapper jaw adapted to trap and hold between them a yarn withdrawn from knitting, an associated cutting device comprising fixed and relatively movable blades arranged scissor fashion for severing a withdrawn yarn, a turnable spindle with which the movable scissor blade is connected so as to turn therewith, the end of the said spindle remote from the cutting device being cranked, a welt mechanism comprising a dial equipped with welt instruments and cams for actuating the said instruments in the production of welts, a selected one of the welt cams having therein a slot in which the cranked end of the aforesaid spindle is engaged so that there is an operative connection between the said welt cam and the cutting device which connection serves normally to maintain the cutting device closed, and means adapted not only to render the said Welt cam operative in the making of a welt but also to move the cam at required times suchwise as to device.

4. In a circular knitting machine, in combination, a welt mechanism comprising a dial equipped with welt instruments and cams for actuating the said instruments in the production of welts, yarn trapping means consisting of a fixed member and a relatively movable trapper jaw adapted to trap and hold between them a yarn withdrawn from knitting, a part which car- .ries a selected one of the welt cams and is arranged normally to press on a formation on the movable trapper .jaw so as normally to lock the latter in co-operative relationship with the fixed member of the trapper, a cutting device comprising relatively movable scissor blades for severing a withdrawn yarn, means which operatively connect the aforesaid selected welt cam with the cutting device and are adapted normally to maintain the latter closed, and means adapted not only to render the said welt cam operative in the making of a welt but also to move the said cam at required times suchwise as to relieve the pressure on and thereby release the movable trapper jaw conjointly with opening of the cutting device.

5. A combination according to claim 1, wherein the selected welt cam is mounted on a guided and spring-controlled carrier block which is normally urged by the spring means to hold the cam inoperative and the cutting device closed.

6. In a circular knitting machine, in combination, a welt mechanism comprising a dial equipped with welt instruments and cams for actuating the welt instruments in the production of welts, including a setting-up cam for rendering the instruments active at the commencement of knitting a welt and the said setting-up cam having a slotted extension, a guided and spring-controlled carrier block upon which the setting-up cam is mounted and by which the said cam is normally held inoperative, yarn trapping means consisting of a fixed member and a pivoted trapper jaw adapted to trap and hold between them a yarn withdrawn from knitting, the tail end of the said pivoted jaw having an extension disposed in the path of the aforesaid cam carrier block so that whenever thelatter is permitted to move under the spring action it comes into contact with and presses upon the tail extension of the pivoted trapper jaw thereby locking the latter in co-operative relationship with the fixed trapper member, a cutting device comprising fixed and relatively movable blades arranged scissor fashion for severing a withdrawn yarn, a turnable spindle with which the movable scissor blade is connected so as to turn therewith, the end of the said spindle remote from the cutting device being cranked and engaged in the slot formed in the extension of the setting-up cam so that there is an operative connection between the said cam and the cutting device which connection serves normally to maintain the cutting device closed, and means adapted not only to render the setting-up cam operative in the making of a welt but also to move the said cam at required times suchwise as to relieve the pressure on and thereby release the movable trapper jaw conjointly with opening of the cutting device.

'7. A combination according to claim 3, Wherethe spindle is mounted to turn in a fixed bracket and is provided with a flange between which and the said fixed bracket is interposed a compression spring serving to hold together yieldingly the blades of the cutting device.

' ALBERT MATTHEWS BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Num er Name Date 2,137,362 Smith et al Nov. 22, 1 938 2,551,385 Miller May 1, 1951 

